Question

Решить системы уравнений 1. а) {х-11у=23 {5х+у=3 (методом подстановки) б) {3х-8у=6 {3х-7у сложения) в) { 5х+у=7 {3х - у графически )

Answer 1

$1)\; \; \left \{ {{x-11y=23} \atop {5x+y=3}} \right.\; \left \{ {{x=11y+23} \atop {5(11y+23)+y=3}} \right.\; \left \{ {{x=11y+23} \atop {56y+115=3}} \right. \; \left \{ {{x=11y+23} \atop {56y=-112}} \right.\\\\\\\left \{ {{x=-2\cdot 11+23} \atop {y=-2}} \right. \; \left \{ {{x=1} \atop {y=-2}} \right.$

$2)\; \; \left \{ {{3x-8y=6} \atop {3x-7y=2}} \right.\; \ominus \; \left \{ {{3x=8y+6} \atop {-y=4}} \right.\; \left \{ {{3x=-8\cdot 4+6} \atop {y=-4}} \right.\; \left \{ {{3x=-26} \atop {y=-4}} \right. \; \left \{ {{x=-\frac{26}{3}=-8\frac{2}{3}} \atop {y=-4}} \right. \\\\\\3)\; \; \left \{ {{5x+y=7} \atop {3x-y=9}} \right. \; \left \{ {{x=2} \atop {y=-3}} \right.$

Answer 2

ответ:лови

Объяснение: